One of the best movies of the year so far, "The Savages" is writer-director Tamara Jenkins' second feature after "Slums of Beverly Hills," which came out a decade ago. If that movie, about a teenage girl's coming-of-age under the guidance of an erratic, unreliable but loving father, was an awakening, this one is a reckoning -- a brutal encounter with mortality told with uncommon humanity, wit and humor. Philip Seymour Hoffman and Laura Linney play a brother and sister who are thrust into caring for the father (Philip Bosco) who never cared for them after he is diagnosed with dementia, forcing them to grow up well past the point at which they've started to age. (Jenkins has called it a "coming of middle age" story.) For a tender, uncommonly perceptive look at sibling relationships and a profound meditation on death and the meaning we draw from experience, "The Savages" is singularly funny and seriously moving.

When Jon Savage (Hoffman) gets the second big phone call regarding his father, Lenny (Bosco), he is halfway through teaching a class on the difference between dramatic theater and epic theater as described by Bertolt Brecht. The first big phone call regarding his father, whose whereabouts had until then been unknown to him, came a few months earlier when his sister, Wendy (Linney), woke him in the middle of the night with the news that Lenny was scrawling nasty messages on the bathroom wall with his feces. In between calls, Jon and Wendy become intimately reacquainted with their estranged father, now suffering from dementia.

From the moment Jon and Wendy arrive in Sun City, Ariz., to remove their father from the home of his recently deceased girlfriend (per her children's wishes), they squabble over minor decisions, gawk in wonder at each other's choices and genuinely worry about one another. A college professor living in Buffalo, Jon teaches theater of social unrest, is writing a book on Brecht and is letting his Polish girlfriend, Kasia (Cara Seymour), go back to Krakow upon the expiration of her visa because he can't bring himself to marry her. His younger sister, Wendy, is a struggling playwright who lives in a tiny East Village apartment, works as a temp, loves her cat and her ficus and dates her married neighbor Larry (Peter Friedman).

Jon is 42, Wendy is 39 -- both siblings have crossed some invisible line into middle age without really noticing it. They are living in a state of arrested emotional development that hints at serious childhood trauma, though not serious enough perhaps to qualify as tragic, which is tough in its own way. When Jon discovers that she has received grant money intended for disaster victims, for instance, he mocks her mercilessly for not having suffered enough to deserve it. Wendy offers some weak defenses, but you can tell deep down she agrees with him. This is the sort of hilarious humiliation Jenkins affixes to run-of-the-mill, bad but not-so-bad-that-Oprah-is-going-to-want-to-hear-about-it suffering.

Hoffman and Linney are eminently believable not only as siblings but as siblings who have survived their mother's abandonment and their father's poor job of raising them. Along with their interest in theater, they share a dark comic sensibility and a highly evolved sense of the absurd. This is something you sense Jenkins shares too -- a perspective of life as theater of the absurd. A longtime resident of New York's East Village whose own father died when she was in her 20s, Jenkins drew inspiration from personal experience. Wendy's life, in particular, seems suspended in a recognizable urban bohemia where it's possible to age without growing up as well as get older while everyone around you seems to stay the same age. This giddy, bittersweet laugh-or-you-might-cry flavor suffuses the movie, making it life-affirming in the most genuine, least sentimental way. It confronts life in all its existential bleakness and finds humor, comfort even joy in small moments.

Bosco performs the difficult task of playing a character whose character has been obscured by dementia. No matter how grumpy or irascible or how alienated from his children he's become, Lenny's condition knocks him into an instant, atavistic familiarity. After not having laid eyes on them in years (Jon and Wendy didn't even know where he lived), Lenny snaps at his kids the minute they walk into the hospital room. "Where have you been?" he yells, as though they'd just let him down yesterday.

Linney is heartbreaking and awe-inspiring as the amazingly perseverant Wendy, who spends her days at tedious temp jobs writing grant proposals in hopes of getting funded to write plays about her difficult childhood. She exercises religiously, indulges her romantic impulses, believes in tidiness and good lighting. Where Wendy works overtime to stave off deterioration and decay, Jon refuses to engage his emotional side, letting his girlfriend go for pragmatic reasons that have nothing to do with how he feels. Hoffman stuffs Jon's sadness and rage into a studied nonchalance that fools no one -- not surprisingly, it's Jon who does most of the notable crying in the film. In one of the movie's most beautiful scenes, he drives to work high on pain medication for a neck injury shortly after his girlfriend's departure, listening to Lotte Lenya sing "The Solomon Song" from "The Threepenny Opera" by Brecht and Kurt Weill. In that moment the bleak, wintry Buffalo streets, with their denuded trees and their sneakers dangling from phone lines, are transformed into something beautiful and mysterious.

That the phone call from the nursing home comes as Jon is contrasting two styles of drama -- which happen to echo his and Wendy's differing styles of seeing and coping with the world -- is a minor background detail that, like of all the details in Jenkins' wrenching, poignant and laugh-out-loud-funny film, sneaks up on you and resonates in surprising ways. After Jon hangs up, one of his students asks, "Mr. Savage? What is the difference between plot and narrative?" Jenkins cuts away before Jon replies. Maybe it's the difference between what happens to us and what we make of what happens to us.